The prior art shows numerous arrangements of valves and ignition means for internal combustion engines as indicated by the following U.S. patents. U.S. Pat. No. 2,609,805 Pescara shows in FIGS. 1-4 an engine having two aligned cylinders per cylinder bank with combustion chambers having push rod actuated overhead valves and oppositely disposed dual spark plugs. The spark plugs extend through the top wall of the cylinder head, requiring an unusual rocker cover and valve gear construction. U.S. Pat. No. 2,827,892 McDuffie et al shows a peaked roof combustion chamber from which dual spark plugs extend through the cylinder head side wall. U.S. Pat. No. 2,833,254 Carpentier et al shows a fast burn modified part-spherical combustion chamber in a V-type engine having overhead valves actuated by push rods from a single centrally located camshaft in conventional fashion. A single spark plug per cylinder opens through the edge of the cylinder head side wall. U.S. Pat. No. 4,116,179 Nagumo et al shows a part-spherical chamber arrangement having dual spark plugs opening through opposite side walls of the cylinder head. Overhead camshaft actuation of overhead valves it utilized.
The prior art fails to illustrate a compact engine arrangement having the benefits of a fast burn part-spherical combustion chamber arrangement having (1) oppositely disposed dual spark plugs that open conventionally through the peripheral walls of the cylinder head below the rocker cover and (2) overhead valves actuated by push rods from a block mounted chamshaft. The latter may allow shorter engine lengths than comparable overhead cam arrangements may also be utilized to operate the valves of more than one cylinder bank. The prior art also fails to suggest a compatible arrangement for push rods, spark plugs and valve gear for such an engine.